检索结果-内蒙古大学图书馆

beijing Ligong Daxue Xuebao/Transaction of beijing institute of Technology 2005年第11期25卷 967-970页

作者： Bi, Le-Peng Zheng, Zhi-Yun Song, Han-Tao Lu, Yu-Chang Department of Computer Science and Engineering School of Information Science and Technology Beijing Institute of Technology Beijing 100081 China State Key Laboratory of Intelligent Technology and System Tsinghua University Beijing 100084 China

Two improvements are introduced into vicinal-risk-minimization based support vector (SV) algorithm. Since the misclassified samples must be support vectors, a scheme for pruning hard-to-learn samples from the training set based on support vectors is presented. The parameter's determination of Gaussian vicinal function is proposed to be modified, based on the maximum likelihood criterion. Preliminary experimental results show that the pruning scheme and improvement of the parameter's determination of vicinal function much improved vicinal SV algorithm's generality, and can outperform support vector machine (SVM) by about 0.5% in test accuracy.

关键词： Learning algorithms

来源：评论

学校读者我要写书评

暂无评论

UNSTEADY FLOWS OF A GENERALIZED SECOND GRADE FLUID WITH THE FRACTIONAL DERIVATIVE MODEL BETWEEN TWO PARALLEL PLATES

引用

Acta Mechanica Sinica 2004年第5期20卷 471-476页

作者：谭文长徐明喻 1 Department of Mechanics and Engineering Science & State Key Laboratory for Turbulence and Complex System Research Peking UniversityBeijing 100871China Institute of Mathematics and Systematical Science Shandong UniversityJinan 250100China

The fractional calculus approach in the constitutive relationship model of a generalized second grade fluid is *** analytical solutions are obtained for a class of unsteady flows for the generalized second grade fluid with the fractional derivative model between two parallel plates by using the Laplace transform and Fourier transform for fractional *** unsteady flows are generated by the impulsive motion or periodic oscillation of one of the *** addition,the solutions of the shear stresses at the plates are also determined.

关键词： fractional derivative unsteady flows generalized second grade fluid parallel plates

来源：评论

学校读者我要写书评

暂无评论

Lie Point Symmetries of Differential-Difference Equations

引用

Communications in Theoretical Physics 2004年第5期41卷 645-648页

作者： DING Wei~1 TANG Xiao-Yan~(2,3) 1 Department of Applied Mathematics,Shanghai Jiao Tong University,Shanghai 200030,China2 Department of Physics,Shanghai Jiao Tong University,Shanghai 200030,China3 state key laboratory of Scientific and engineering Computing,institute of Computational Mathematics and Scientific engineering Computing,Academy of Mathematics and system Sciences,the Chinese Academy of Sciences,P.O.Box 2719,beijing 100080,China State Key Laboratory of Scientific and Engineering Computing Institute of Computational Mathematics and Scientific Engineering Computing Academy of Mathematics and System Sciences the Chinese Academy of Sciences P.O. Box 2719 Beijing 100080 China

In this paper,the classical Lie group approach is extended to find some Lie point symmetries of differential-difference *** reveals that the obtained Lie point symmetries can constitute a Kac-Moody-Virasoro algebra.

关键词： Lie point symmetry differential-difference equation Kac Moody-Virasoro algebra

来源：评论

学校读者我要写书评

暂无评论

Teracluster LSSC-II--Its designing principles and applications in large scale numerical simulations

引用

中国科学A辑（英文版） 2004年第z1期47卷 53-68页

作者： Zhang Linbo Chen Shiyi LI Xinliang CAO Jianwen ZHANG Wensheng GONG Xingao State Key Laboratory of Scientific and Engineering Computing Academy of Mathematics and System Sciences Chinese Academy of Sciences Beijing 100080 China Department of Mechanical Engineering The Johns Hopkins University and Center for Computational Science and Engineering Peking University Beijing 100875 China Institute of Mechanics Chinese Academy of SciencesBeijing 100080 China Parallel Computing Laboratory Institute of Software Chinese Academy of Sciences Beijing 100080 China Academy of Mathematics and System Sciences Chinese Academy of Sciences Beijing 100080 China Surface Physics Laboratory National Key Laboratory Fudan University Shanghai 200433 Institute of Solid State Physics Chinese Academy of Sciences Hefei 230031 China

The teracluster LSSC-II installed at the state key laboratory of Scientific and engineering Computing, Chinese Academy of Sciences is one of the most powerful PC clusters in China. It has a peek performance of 2Tflops. With a Linpack performance of 1.04Tflops, it is ranked at the 43rd place in the 20th TOP500 List (November 2002), 51st place in the 21st TOP500 List (June 2003), and the 82nd place in the 22nd TOP500 List (November 2003) with a new Linpack performance of 1.3Tflops. In this paper, we present some design principles of this cluster, as well as its applications in some large-scale numerical simulations.

关键词： high performance computing PC cluster large scale numerical simulations

来源：评论

学校读者我要写书评

暂无评论

Aging effect of UV radiation on SIR insulators' hydrophobicity property

Aging effect of UV radiation on SIR insulators' hydrophobici...

引用

Conference on Electrical Insulation and Dielectric Phenomena, (CEIDP)

作者： Xun Wang Xidong Liang Yuanxiang Zhou State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing China

ISBN: (纸本)0780385845

Based on the simulation of ultraviolet (UV) radiation in the Sun's rays and in corona, the aging effect of UV radiation on composite insulators was studied in this paper, especially the effect on hydrophobicity properties. It is found that after irradiation with UV, no matter whether a short time of less than 24 hours or a long time of 2000 hours, the hydrophobicity and the hydrophobicity transfer properties of silicone rubber (SIR), which are described by contact angle, slowly turns better. Four different kinds of samples with different prescriptions were used in the test. As UV sources, a special setup to simulate the UV rays of corona and a xenon light to simulate the sunlight were both used. The change of rigidity of silicone rubber was also measured. Infrared spectra of the silicone rubber surface, irradiated by UV for various times, show that the content of the low molecule weight on the surface is different, and this can be due to the discrepancy of hydrophobicity properties of the samples.

关键词： Aging Testing Slabs Xenon Corona Rubber Power system simulation Surface cleaning Dielectrics and electrical insulation Stress

来源：评论

学校读者我要写书评

暂无评论

Influence of annealing method on the space charge properties in polyethylene

Influence of annealing method on the space charge properties...

引用

Conference on Electrical Insulation and Dielectric Phenomena, (CEIDP)

作者： Ninghua Wang Yuanxiang Zhou Hongbin Liu Bin Gao Xidong Liang Zhicheng Guan T. Takada State Key Laboratory of Control and Simulation of Power System and Generation Equipment Tsinghua University Beijing China Electronic Measurement Laboratory Musashi Institute of Technology Tokyo Japan

In this paper, high-density polyethylene (HDPE) films were prepared by three kinds of annealing methods which were different in cooling speed. The crystallinity of those HDPE samples were measured and compared. A high DC voltage was applied to the samples and the space charge formed was measured. Homo-charges were found in samples that were applied with a negative high voltage. The space charge properties were discussed, based on crystallinity. From these results, it is found that the space charge formed in samples cooled at high speed is more than that of the samples cooled at normal and low speed.

关键词： Annealing Space charge Polyethylene Voltage Current measurement Charge measurement Conducting materials Crystallization Morphology Laboratories

来源：评论

学校读者我要写书评

暂无评论

Construction and Analysis of Structured Preconditioners for Block Two-by-Two Matrices

引用

Journal of Shanghai University(English Edition) 2004年第4期8卷 397-405页

作者：白中治 State Key Laboratory of Scientific/Engineering Computing Institute of Computational Mathematics and Scientific/Engineering Computing Academy of Mathematics and System Sciences Chinese Academy of Sciences Beijing 100080 P.R. China

For the large sparse block two-by-two real nonsingular matrices, we establish a general framework of structured preconditioners through matrix transformation and matrix approximations. For the specific versions such as modified block Jacobi-type, modified block Gauss-Seidel-type, and modified block unsymmetric (symmetric) Gauss-Seidel-type preconditioners, we precisely describe their concrete expressions and deliberately analyze eigenvalue distributions and positive definiteness of the preconditioned matrices. Also, we show that when these structured preconditioners are employed to precondition the Krylov subspace methods such as GMRES and restarted GMRES, fast and effective iteration solvers can be obtained for the large sparse systems of linear equations with block two-by-two coefficient matrices. In particular, these structured preconditioners can lead to high-quality preconditioning matrices for some typical matrices from the real-world applications.

关键词： block two-by-two matrix preconditioner modified block relaxation iteration eigenvalue distribution positive definiteness.

来源：评论

学校读者我要写书评

暂无评论

Review of the Study of Nonlinear Atmospheric Dynamics in China (1999-2002)

引用

Advances in Atmospheric Sciences 2004年第3期21卷 399-406页

作者：刁一娜封国林刘式达刘式适罗德海黄思训陆维松丑纪范 Department of Atmospheric and Oceanic Sciences Ocean University of China Qingdao 266003 State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid DynamicsInstitute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 Department of Atmospheric Sciences Peking University Beijing 100871 Department of Atmospheric and Oceanic Sciences Ocean University of China Qingdao 266003 P. L. A. University of Science & Engineering Meteorological Institute Nanjing 211101 Nanjing Institute of Meteorology Nanjing 210044 Beijing Training Center China Meteorological Administration Beijing 100081esearches on nonlinear atmospheric dynamics in China (1999-2002) are briefly surveyed. This review includes the major achievements in the following branches of nonlinear dynamics: nonlinear stability theory nonlinear blocking dynamics 3D spiral structure in the atmosphere traveling wave solution of the nonlinear evolution equation numerical predictability in a chaotic system and global analysis of climate dynamics. Some applications of nonlinear methods such as hierarchy structure of climate and scaling invariance the spatial-temporal series predictive method the nonlinear inverse problem and a new difference scheme with multi-time Ievels are also introduced.

Researches on nonlinear atmospheric dynamics in China (1999-2002) are briefly surveyed. This review includes the major achievements in the following branches of nonlinear dynamics: nonlinear stability theory, nonlinear blocking dynamics, 3D spiral structure in the atmosphere, traveling wave solution of the nonlinear evolution equation, numerical predictability in a chaotic system, and global analysis of climate dynamics. Some applications of nonlinear methods such as hierarchy structure of climate and scaling invariance, the spatial-temporal series predictive method, the nonlinear inverse problem, and a new difference scheme with multi-time Ievels are also introduced.

关键词： nonlinear dynamics stability blocking spiral structure traveling wave global analysis

来源：评论

学校读者我要写书评

暂无评论

Edge Effect Correction in the S-A Method for Geochemical Anomaly Separation

引用

Journal of China University of Geosciences 2004年第4期15卷 379-387页

作者： Ge Yong Department of Earth and Atmospheric Science, York University, Toronto, ON, M3J 1P3, Canada state key laboratory of Resources and Environmental Information system, institute of Geographic Sciences & Natural Resources Research, Chinese Academy of Sciences, beijing 100101, China Cheng Qiuming Department of Earth and Atmospheric Science, York University, Toronto, ON, M3J 1P3, Canada Earth systems and Mineral Resource engineering Lab, China University of Geosciences, Wuhan 430074, China Zhang Shenyuan Department of Earth and Atmospheric Science, York University, Toronto, ON, M3J 1P3, Canada Department of Resource and Earth Science, China University of Mining & Technology, beijing 100083, China Department of Earth and Atmospheric Science York University Toronto ON M3J 1P3 Canada State Key Laboratory of Resources and Environmental Information System Institute of Geographic Sciences & Natural Resources Research Chinese Academy of SciencesBeijing 100101China Department of Earth and Atmospheric Science York University Toronto ON M3J 1P3 Canada Earth Systems and Mineral Resource Engineering Lab China University of Geosciences Wuhan 430074 China Department of Earth and Atmospheric Science York University Toronto ON M3J 1P3 Canada Department of Resource and Earth Science China University of Mining & Technology Beijing 100083 China

Anomaly separation using geochemical data often involves operations in the frequency domain, such as filtering and reducing noise/signal ratios. Unfortunately, the abrupt edge truncation of an image along edges and holes (with missing data) often causes frequency distribution distortion in the frequency domain. For example, bright strips are commonly seen in frequency distribution when using a Fourier transform. Such edge effect distortion may affect information extraction results; sometimes severely, depending on the edge abruptness of the image. Traditionally, edge effects are reduced by smoothing the image boundary prior to applying a Fourier transform. Zero-padding is one of the most commonly used smoothing methods. This simple method can reduce the edge effect to some degree but still distorts the image in some cases. Moreover, due to the complexity of geoscience images, which can include irregular shapes and holes with missing data, zero-padding does not always give satisfactory results. This paper proposes the use of decay functions to handle edge effects when extracting information from geoscience images. As an application, this method has been used in a newly developed multifractal method (S-A) for separating geochemical anomalies from background patterns. A geochemical dataset chosen from a mineral district in Nova Scotia, Canada was used to validate the method.

关键词： edge effect correction fractal modeling spatial information extraction zero-padding decay functions.

来源：评论

学校读者我要写书评

暂无评论

On the regularity of trust region-cg algorithm: With application to deconvolution problem

引用

Science China Mathematics 2003年第3期46卷 312-325页

作者：王彦飞 Laboratory of Remote Sensing Information Sciences Institute of Remote Sensing ApplicationsChinese Academy of Sciences State Key Laboratory of Scientific and Engineering Computing Institute of Computational Mathematicsand Scientific/Engineering ComputingAcademy of Mathematics and System SciencesChinese Academy of SciencesBeijing 100080China

Deconvolution problem is a main topic in signal processing. Many practical applications are re-quired to solve deconvolution problems. An important example is image reconstruction. Usually, researcherslike to use regularization method to deal with this problem. But the cost of computation is high due to thefact that direct methods are used. This paper develops a trust region-cg method, a kind of iterative methodsto solve this kind of problem. The regularity of the method is proved. Based on the special structure of thediscrete matrix, FFT can be used for calculation. Hence combining trust region-cg method with FFT is suitablefor solving large scale problems in signal processing.

关键词： ill-posed problems, efficient implementation, trust region-cg method, regularity.

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：